DESCRIPTION (Applicant's Abstract): This continuation proposal extends the applicant's investigations into the expressive microstructure of music - the systematic variations in timing, dynamics, and articulation that make performed music expressive and aesthetically appealing. The aim of the research is to investigate specific issues in the perception, production, and evaluation of expressive microstructure, primarily by musically trained individuals. The focus is on timing in piano performance, and the experiments make innovative use of computer-controlled pianos and MIDI technology for data collection and stimulus generation. The perceptual studies are concerned with the detection of timing perturbations in musical excerpts as a probe into the structural determinants of expressive timing. These studies investigate a previously demonstrated close relation between timing perception and performance and try to determine its causes. Experimental studies of music performance and aesthetics focus on the interaction of timing with other expressive dimensions (tempo, dynamics) and on the relation between typicality and aesthetic preference. Analyses of performances of the same music by different pianists will assess individual differences in interpretation and look for objective hallmarks of expertise, aiming at a better understanding of conventionality and originality, the two opposing forces guiding music performance. By investigating expressive microstructure from many angles, the applicant hopes to build bridges between music psychology and other ares (including kinematics, musicology, and aesthetics) and to achieve a better understanding of the nature of expressiveness in Western classical music, a sophisticated system of nonverbal communication that greatly enhances the quality of lives of many individuals.